Bobby Womack, the revered “poet” of soul music for his prowess as a songwriter as well as singer and guitarist, died Friday at 70.

Representatives of Womack’s label, XL Recordings, confirmed the death. The cause wasn’t immediately known, but he had been battling diabetes and had cancer surgery in 2012.

Womack’s greatest work spanned decades. He was an in-demand session musician as a guitarist, a distinctively gritty vocalist and a renowned songwriter. Womack’s “It’s All Over Now” became a No. 1 hit when the Rolling Stones covered it in 1964 and his “Across 110th Street” enjoyed a revival when Quentin Tarantino made it the centerpiece of his soundtrack for the 1997 “Jackie Brown” movie. He has worked with, written for and inspired generations of artists, including Jimi Hendrix, Chaka Khan, Aretha Franklin, Sly Stone, Elvis Presley, and Gorillaz’s Damon Albarn.

Womack was born in Cleveland in 1944 and began performing and later recording gospel music with his brothers Curtis, Harry, Cecil and Friendly in the ‘50s. The Womack Brothers established a strong Chicago connection early on, performing frequently in the city. They were mentored by South Side native Sam Cooke, who signed them to his SAR label in 1960, and they went on national tours with the Staple Singers. The group found commercial success when it changed its name to the Valentinos and shifted to a more secular soul sound.

His extensive session work in the ‘60s included hits for Aretha Franklin, the Box Tops and Joe Tex, and writing songs for artists such as Wilson Pickett. He played guitar in Cooke’s band, and a few months after Cooke was killed in 1964, he wed Cooke’s widow, Barbara Campbell, which caused a scandal and got his career as a solo artist off to a bumpy start.

But as Womack began making his own albums, his substantive songs won favor from tastemakers such as “Soul Train” host Don Cornelius, who used to book him for Chicago concerts before the promoter’s TV show went national.

“Chicago is old stomping grounds for me,” Womack told the Tribune in a 2012 interview. “Don Cornelius used to bring me in, when they were very fearful of me because I married Sam’s wife. There were so many negative feelings about me. But I loved to sing so much, being young and naïve, all I thought I needed to do was come in and perform. If I’m a true entertainer I have to perform anywhere. It was a big thing for me to win over the crowd. (Chicago soul radio DJ) E. Rodney Jones would always bring me in. He said, ‘Bobby, you keep being you, they’ll join you.’

“One day in the 1970s, we had a big date at McCormick Place. That was great news. I got paid a nice price to come in, but the promoter came in and said, ‘We got bad news, your band had a bus wreck. Nobody got hurt, but all the instruments got torn up. We got to take our money back, or you got to go out and perform without them. It’s up to you.’ I had my acoustic guitar, so I started to perform by myself. I started to talk to the crowd like I’m talking to you on the phone. I played some songs I never recorded. I went into some of these songs, told jokes about me and Sam coming up. I walked off, got a standing ovation. It was a full house. I never forgot that.”

Womack made a series of acclaimed albums in the ‘70s and early ‘80s, including “The Poet,” a No. 1 R&B hit in 1981, that attested to his vision as a lyricist whose songs brimmed with vivid details about everything from domestic affairs to street life. He wrote about adult issues, and embodied characters from the preacher to the philanderer, ever the philosopher about the everyday travails in the inner-city.

His R&B hits during this fertile era included “That’s the Way I Feel About Cha,” “Woman’s Gotta Have It,” “Across 110th Street,” “Lookin’ for a Love” and “If You Think You’re Lonely Now.”

But drug addiction set him back for much of the next two decades, as he recorded only sporadically and his health deteriorated. In 2010-11, Albarn invited Womack to record and go on tour with Gorillaz, and produced the singer’s 2012 comeback album, “The Bravest Man in the Universe.”

Womack said he had no idea who Albarn was until his daughter informed him. “I told her they (Gorillaz) wanted me to sing on a single they had coming out,” Womack told the Tribune. “She said, ‘Dad, that’s a break for you.’ But my break was being able to do what I wanted to do. Damon just wanted me to be me.”

He said he was grateful to be working again and was determined to stay healthy so he could keep touring. “I know a lot of people aren’t here anymore and I wonder why I’m still here,” he said. “Not a day goes by that I don’t think about Sam (Cooke). His presence is so strong and so convincing to me, a true artist, a true talent. When you’ve been around Cooke, Marvin Gaye, James Brown, Wilson Pickett – all those people had styles. Nobody sounded like nobody else. To keep up, you write a song, and you keep writing them, and you get better, you find your voice. Great lyrics never go out of style.”